One thing that does happen when you're asleep is that your saliva dries up. Saliva's really important because it contains substances that switch off bacteria. Your mouth is a seething mass of bacteria, and some of them produce compounds that contain a lot of sulphur. Those sulphurous compounds are quite whiffy. I think therefore, that when you go to sleep, your breath gets quite smelly and you end up breathing out lots of dry mouth bacterial action, and it makes your room smelly and stale.

He says that in Matthew chapter 16 vs. 2-3, Jesus says to the Pharases 'when it's evening ye say, it will be fair weather for the sky is red. And in the morning it will be foul weather for the sky is red and lowering.' So that goes to show that for 2000 years or so, variants of this saying have been in use. But what's the theory behind it? Here in the Northern Hemisphere, the prevailing wind direction is usually going from the east towards the west. If you want there to be a red sky in the morning or the evening, there have to be clouds on the horizon where the sun is. If you think of red sky at night shepherd's delight, then the sun will be setting in the west, and the clouds must also be in the west for the sky to be red. Since the prevailing wind direction is going towards the west, that would suggest that the clouds are being blown away, leaving clear skies. If clouds are assumed to be associated with bad weather, then red sky at night would predict a good clear day the next day. That leaves us with red sky in the morning, shepherd's warning. Well the reason for that would be that the sun is coming up in the east, and so the clouds would also have to be in the east. Since they're likely to be blown towards you during the day, potentially bringing bad weather, that's why red sky in the morning might be a shepherd's warning. That seems like a reasonable explanation to me, so thanks very much to James for sending that in.

The first thing we need to think about is gravity itself. When you're stood on the surface of the earth, the gravity that's affecting you is from the whole mass of the earth beneath your feet. As you move towards the centre of the earth, the amount of mass beneath your feet is decreasing. So when you get to the centre, the force of gravity exerting on you would be zero. But by this stage you would have reached a velocity, so you would pass through the centre and move through the other side. However, then gravity will start working on you again, and you will be pulled back down towards the centre. Therefore, you will oscillate. If you assume that there is air all around you, there would be air resistance, which would cause you to lose some energy along the way. This would cause you to eventually come to a stand still. As for the air pressure, if you look at a deep sea diver, for every ten metres they go down under the sea, they get the equivalent of the whole earth's atmosphere on top of them again. The reason that this isn't a problem for them is because it's pressing on them in all directions. It's both inside and outside, so it all equalises out. So I don't think that you would be squashed flat. You would probably get the bends though, because you'd be flying out of the hole so fast.

Although there's evidence that the bird flu virus can spread around the body of the birds that it infects, there's not any evidence to show that it can get inside eggs, but it does come out the intestines. So it's possible that the outside of the egg could get infected with some virus particles, and if you ate it raw, you could potentially contaminate things. But if you cook it properly, such as along the lines that you're suggesting, it will be fine because flu is just a bag of genes, or protein containing genetic material. If you heat that up properly, it should just fall apart and neutralise it. I don't actually think that there's any risk to your health and you can go on enjoying your balot with no problems at all.

If the colours were down to inks or pigments, they would fade, just as if you wrote on a piece of paper and left it for many many years. If you go to the museums around the world, hundreds of years ago people collected some wonderful specimens of butterflies and moths that had some beautiful colours. If you look at those today, they still look spectacular. This means that they don't have inks. What they have got is a very clever arrangement of substances that bend and reflect light in just the right way using the structure of the shapes of what's in the wings to make those colours. It's what's called structural colour. The reason they have those beautiful patterns is actually down to camouflage and defence. Butterflies are a very juicy snack for things like birds and bigger animals, so they need to try and blend in with their environment. One way they can do that is to look the same as their environment, by having the same colour wings as what they like to live on. Other butterflies have shapes on their wings that look like a face. This scares off any potential predators. That's why they have their interesting colours.

That's a very interesting question. Sometimes people say that people who claim to have had UFO experiences have actually been watching too much science fiction. But actually I find that the true position is the exact opposite of that. Science fiction writers and famous film directors actually go out and talk to UFO witnesses about the things that they have seen. A classic example of this is the film Close Encounters of the Third Kind. Steven Spielberg, went out researching and he used a chap called Dr J. Allen Hynek as one of the consultants on the film. Hynek used to run the US Government's UFO project. Interestingly, right at the end of the film when the mother ship comes over the base, Spielberg rated Hynek's contribution so highly that he gave him a cameo role in the film. He's the old guy with a pipe. So film-makers get all their information from UFO research, not the other way round.

Cigar-shaped objects are some of the most commonly sighted UFOs that are seen. Another common shape is a large triangular UFO. I think to a certain extent, the shape you will perceive will depend on the angle from which you are observing it. Also, I don't know whether you were observing this thing through glass, but sometimes this can have a distorting effect. It's interesting that you mention the police saw something too, because when I was working on the UFO project, sightings by trained observers such as military personnel were very important.

It's a fascinating encounter. Far from the typical view that people think that alien encounters only happen down a lonely lane in the country, that UFOs are seen in multiple witness events over our major cities, such as London.

Well there were a large number of sightings around that time, so it may have been the same as that seen in Rendlesham.

I can't really say much about the individual sighting. I investigate about 300 or 400 sightings a year. Most of them have conventional explanations, but about 5% don't. Those are the ones that I'm particularly interested in. There's such tremendous interest in this at the moment, and it's no coincidence that the Science Museum at the moment has a new exhibition called The Science of Aliens. This subject really is in the public eye at the moment.